This invention relates to general categories of a fuel injection system which have common configurations and structural arrangements for internal combustion engines. In particular, this invention relates to injector systems which are able to operate using the xe2x80x9cself injectionxe2x80x9d concept, and/or the xe2x80x9ccommon railxe2x80x9d concept, and includes the xe2x80x9cmultiple injection per cyclexe2x80x9d concept, particularly using the concept of xe2x80x9cself-induced pulsations.xe2x80x9d These concepts have been the subject of our prior patented technology. The universal fuel injection system improves upon the prior patented technology and is the main subject of this new invention.
A general attribute that is characteristic of one embodiment using the xe2x80x9cuniversal fuel injection systemxe2x80x9d and xe2x80x9cself-induced multiple injectionsxe2x80x9d is the ability to be associated with and incorporated into any existing or new injection systems.
The general attribute is further enhanced by the modular structure of the preferred implementation which can be flexibly configured for different injection systems, depending on a particular application.
For land transportation, cars, busses, trucks, naval propulsion, locomotives, the main sources of fuel have been liquids, including diesel fuels, kerosene and gasoline, all of them based on petroleum resources.
Natural gas was not sufficiently available to the commercial market for existing vehicles, including more than 600 million, spark ignited and diesel powered vehicles. The conventional, conversion technology, from liquid fuels to natural gas, results in a severe degradation in the performance, resulting in a lower power density and reduced efficiency.
The typical technology, based on the intake of the natural gas and air in a common admission, diminishes the air volume by the gas volume, typically resulting in a 50% reduction of the effective power and thermal efficiency, caused, for example, by the reduction of the compression ratios in a diesel engine from an original 18-20/1 to a resultant 10-11/1.
In contrast, direct injection of the liquid and gas fuels conserves the air capacity and the high compression ratio of the engine for a retained maximum power density and thermal efficiency.
A first objective of this invention is the general and universal capability to directly inject all the liquid fuels, and all the gaseous fuels, like natural gas, compressed natural gas (CNG), or liquefied natural gas (LNG), hydrogen, hydro-ammonia, etc.
A second objective of this invention is the capability that the transition from one fuel to any other can be manual or automatic, or commanded or programmed.
A third objective of this invention is that the universal injector can inject blended fuels from different categories and in different proportions mixing of liquids with liquids, or liquids and gases.
A fourth objective of this invention is the capability to be modularized, integrated and associated on conventional injection systems, on conventional common rails, and in any self-injection system, having the Common Universal Fuel Injector.
A fifth objective of this invention is the universal applicability, with practically insignificant or no modification at all, to any and all categories of engines, whether two stroke, four stroke spark-ignited or four stroke diesel.
A sixth objective of this invention is a constant pressure, direct natural gas injection, using constant pressure natural gas containers, pressurized by liquid fuel injection, with equal volume in accordance with the gas volume injected in the cylinder.
All the existing injection systems whether conventional, or new, electronically controlled or mechanically actuated, can be fundamentally improved by the association and integration of the universal fuel injector of this invention.
A first embodiment of the xe2x80x9cuniversal fuel injectorxe2x80x9d is in a working injection system, as described in the referenced patent, where a xe2x80x9cself injection systemxe2x80x9d related to a fuel injection system suitable for any internal combustion engines, wherein the developed pressure within the compression and combustion chamber is utilized to generate the amplified fuel injection pressure.
The new improvement introduces a number of novel features and advantages over and above those already described in the referenced patent for a xe2x80x9cself injection systemxe2x80x9d.
The most important feature introduced by these improvements is the xe2x80x9cuniversal fuel injector,xe2x80x9d which can directly inject any xe2x80x9cliquid fuels,xe2x80x9d of any nature, can directly inject any combination of xe2x80x9cliquids with liquid,xe2x80x9d for example alcohols with petroleum fluids, without the necessity of using surfacents, water and any liquid or gaseous fuels, alternatively can automatically switch to high pressure natural gas CNG and/or LNG, direct injection, as long as the high pressure of the gas is available. Automatically, the universal fuel injector is switched back to liquid fuel injection when or if the high pressure gas is not available, which is permitting the vehicles a continuous operation without any interruption. All these features and advantages are part of the definition of the xe2x80x9cuniversal fuel injection system.xe2x80x9d
Another essential advantage introduced is the separation between the universal fuel injector module and all the associated injection systems permitting a simple replacement of the existing injector of any engine with the new universal fuel injector module.
A new and specific embodiment of the referenced invention of the xe2x80x9cself injection systemxe2x80x9d is the inclusion of the xe2x80x9cuniversal fuel injector modulexe2x80x9d in a preferred embodiment of this invention forming a universal fuel, self injection system. The most important advantage introduced by these improvements is the modular separation between all the functional components, like the actuating module, the high pressure injection module and the universal fuel injector module.
This system enables independent control of all the parameters of the injection mixture formation and a perfect clean combustion. The modular system allows flexible structural variations depending on specific applications. Features of the improved injection system, originating in the referenced patent, include a hydraulic cylinder actuating module, with a slidable amplifier piston that is provided with an electronic/hydraulic control valve system, having a commanding plunger that is xe2x80x9chydraulically unbalanced.xe2x80x9d
This control module controls the access to the source of pressurized actuation fluid over the xe2x80x9chydraulically unbalanced plungerxe2x80x9d and is able to control the opening to the source of the pressurized fluid at the start of the injection. The high pressure injection module is provided with an electro hydraulic valve, which controls the general pressurization, and the timing of the xe2x80x9csharp cutxe2x80x9d of the end of injection. The same high pressure injection module is preferably provided with the self-induced multiple injection sub-module. Finally, individual modules of the modularized self-injection system described above, or any existing or new injectors, can be associated with the xe2x80x9cuniversal fuel injector module, which is the main object of this invention.
In the type of injection systems featuring the self-injection concept, the compression and the combustion pressure of the gases in the combustion chamber of the engine, on which the injector is mounted, provide the driving pressure for pressurizing the actuation fluid (engine oil or fuel). In this manner, the pressure of the liquid injection fuel, as amplified 10-15 times by the hydraulic actuator, profiles the pressure developed in the combustion chamber. The newly formed injection system directly utilizes the effect of the pressure evolution in the thermal cycle to induce in the fuel injection process a proportional, triangular evolutive pressure, This profile is absolutely ideal for the formation of an air-fuel mixture for a perfect, clean combustion process.
A second embodiment of the invention of this injection system comprises a working injection system, based on the common rail concept, in which the hydraulic pressure source is a medium pressure fuel pump (approx. 4000 psi). This configuration is provided with a balanced electro-hydraulic valve and a common by-pass discharge communication between the hydraulic actuator module and the high pressure injection module.
The new modularized injection system is preferably associated with the described xe2x80x9cuniversal injector module,xe2x80x9d which is able to direct inject all the categories of liquids and gaseous fuels, individually or combined in any and all proportions, simultaneous or alternatively.
The injection nozzle is provided with a new poppet injection valve, which generates a conic shaped injection spray, equivalent to a nozzle with an infinite number of holes and a high speed vortex generator for spinning the fuel, which generates high intensity centrifugal accelerations of the fuel molecules, producing an explosive dispersion of the fuel and air mixture. This type of fuel injector generates a total homogenization of the fuel air mixture, and is a complete total departure from the non-homogenous fuel mixture of the typical diesel, which is responsible for the usual emission of all the pollutants including NOx and particulate matter.
The universal fuel injector module, which is one of the main features of this invention, is provided with a switch valve for alternately commuting the operation between pure liquid and high pressure gas-liquid, In the direct, high pressure, gas-liquid operation mode, the poppet valve is provided with a central channel for liquid fuel, and a pilot liquid fuel injection holes concentric with the vortex of high speed, high pressure gas directly injected in the combustion chamber. The combined fuels generate a homogenous gas-liquid super mixture, ignited by the liquid-fuel pilot injection.
The universal fuel injector module of this invention can be individually associated and integrated in any and all type of injection systems existing or new, including those with in line injection pumps mechanically driven by the engine, or conventional electronic hydraulic common rail injection systems, which is a xe2x80x9cuniversal characteristicxe2x80x9d of this new injection system.
A special category for highly supercharged engines, represented in an alternate embodiment of the self injection system described above, is designed to enable a very large quantity of fuel to be injected in a very short time.
All of these injection systems can be electronically controlled based on an optimized map of operation for all the regimes of power, torque, rotation and level of supercharging. The electronically controlled system utilized modern smart sensors for diagnosing, and continuously comparing the optimized and the real time cycle parameters, cycle by cycle. Such system is controlled by a central electronic module which enables cycle corrections for all potential deviations from the map of optimum conditions.
Since the regulation of any and all the cycle parameters is automatic, the control function of the electronic control module is easily extended over all conditions for each injector. The capability of individual self-control of the injection process for each cylinder enables the system to self-diagnose and to equalize all the factors in an absolute regime of cooperative operation. This result is a self-regulating system for uniform operation of each injector in the entire engine system.
By appropriate modification, the design of the self-injection system can be extended to spark ignited engines for operating lean and ultra lean and clean combustion without departing from the spirit of this invention.